This research program deals with four aspects of nervous system function: 1) properties of excitable membranes; 2) sensory and synaptic transduction at the cellular level; 3) information transfer from sense organs to the CNS; and 4) use and disuse, trophic factors, development and regeneration of nervous structures, particularly those of sensory systems. This program involves 13 investigators who have collaborated in several aspects of these problems. These studies involve carotid body chemoreceptors, invertebrate photoreceptors, ionic mechanisms in excitable tissues, mammalian sensory pathways, development and regeneration of sensory structures. Special emphasis is given in most projects to correlation of function and structure in normal and abnormal conditions. The support requested is basically for partial faculty salaries, salaries for key technical personnel, equipment to improve computational and neurochemical facilities already available and supply monies to improve and expand these and our ultrastructural research facility. Eleven investigators have their own research grants approved and funded. The overall purpose of this application is to provide core support and partial investigators' salaries to study the nervous functions described above as a group. This approach has proven successful in the past and it is expected that continued success will be possible by the support requested in this application.